钩子的问题

[lght]

翻了MSDN，上面说可以阻止消息传递给目标窗口，这个怎么弄？

还说可以修改消息，我拦截了WM_SETTEXT，修改了消息中的窗口内容的那个参数，显示出来的还是原来的文字，这个怎么改？

[iqyely]

学习下。

[cnzdgs]

WH_GETMESSAGE可以修改消息，WH_CALLWNDPROC不能修改，通过SendMessage发送的消息都不经过WH_GETMESSAGE，所以都不能修改。
可以利用钩子将代码注入到目标进程，再通过用SetWindowLong替换窗口的WNDPROC，在自己的窗口函数中修改消息。

[lght]

Hooks provide powerful capabilities for Windows-based applications. These applications can use hooks to:

Process or modify all messages meant for all the dialog boxes, message boxes, scroll bars, or menus for an application (WH_MSGFILTER).
Process or modify all messages meant for all the dialog boxes, message boxes, scroll bars, or menus for the system (WH_SYSMSGFILTER).
Process or modify all messages (of any type) for the system whenever a GetMessage or a PeekMessage function is called (WH_GETMESSAGE).
Process or modify all messages (of any type) whenever a SendMessage function is called (WH_CALLWNDPROC).
Record or play back keyboard and mouse events (WH_JOURNALRECORD, WH_JOURNALPLAYBACK).
Process, modify, or remove keyboard events (WH_KEYBOARD).
Process, modify, or discard mouse events (WH_MOUSE).
Respond to certain system actions, making it possible to develop computer-based training (CBT) for applications (WH_CBT).
Prevent another filter from being called (WH_DEBUG).

http://msdn.microsoft.com/en-us/library/ms997537.aspx
难道MSDN忽悠我？

[Mit1208]

嘿..他感觉你好欺负.

[天火]

有意思，顶一下。

[cnzdgs]

在你贴出的链接的中间部分，“Types of Hooks”下面：
WH_CALLWNDPROC
Windows calls this hook whenever the Windows SendMessage function is called. The filter functions receive a hook code from Windows indicating whether the message was sent from the current thread and receive a pointer to a structure containing the actual message.

The CWPSTRUCT structure has the following form:

Copytypedef struct tagCWPSTRUCT {
LPARAM lParam;
WPARAM wParam;
DWORD message;
HWND hwnd;
} CWPSTRUCT, *PCWPSTRUCT, NEAR *NPCWPSTRUCT, FAR *LPCWPSTRUCT;

Filters can process the message, but cannot modify the message (this was possible in 16-bit Windows). The message is sent to the Windows function for which it was intended. This hook is a significant drain on system performance, especially when it is installed as a systemwide hook, so use it only as a development or debugging tool.

[husion01]

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